In some applications, it is desirable to ensure that only certain cables are plugged into certain jacks of a wall plate or similar device. One way to do this is to use physically “keyed” plugs and jacks that are designed to be used with one another. That is, only a keyed plug specially designed to be used with a keyed jack can be inserted into the keyed jack and successfully establish a connection using that keyed jack. Such physical keying techniques can be used with various types of cables including, for example, copper cables (such as ETHERNET cables that are terminated with keyed RJ-45 jacks) and fiber optic cables (such as optical cables that are terminated with keyed LC and MTP connectors).
Some applications, however, may require an additional layer of security beyond that which may be provided by such physical keying techniques.
In some applications, it is desirable to use Virtual Local Area Networks (VLANs). A network manager uses VLAN techniques to logically segment a physical Local Area Network (LAN) into different logical broadcast domains, where each logical broadcast domain is a separate VLAN. VLANs are used for many reasons (for example, to improve security or performance, simplify administration, or reduce costs). The Institute of Electrical and Electronics Engineers (IEEE) 802.1Q standard defines how VLANs can be implemented on ETHERNET networks.
When a particular end device is to be assigned to a particular VLAN, the network switch that the end device is directly connected to needs to be configured to insert appropriate VLAN tags into data frames received from the end device. The configuration of such edge network switches can be complex and error prone, especially when done manually.